1. Field of the Invention
This invention relates to an ignitor for a rocket engine, and more specifically, to a hypergolic liquid ignitor for use with a rocket engine, such as the MC-1 engine.
2. Prior Art
Various hypergolic ignitor designs have been developed in the past. These ignitors are utilized to commence the burning of the rocket engine propellants in the combustion chamber. Hypergolic fluid is designed to ignite spontaneously upon contact with an oxidizer. The prior art ignitors are mounted off the main injector of the rocket engine and are typically incorporated into a fuel bypass line feeding the injector. These ignitors dispense the hypergolic fluid through the injector into the combustion chamber where the fuel was ignited. Fuel pressure from the feed or fuel system forces the ignitor fluid into the combustion chamber where it ignites the rocket engine propellants.
The traditional hypergolic ignitor designs suffer from a plurality of disadvantages. First, they are typically non-reusable and expensive to construct since they are not constructed with off-the-shelf components. Secondly, the filling of the prior art ignitors requires a high degree of complexity. Furthermore, the prior art ignitors deliver the ignitor fluid through the combustion chamber injector instead of directly into the combustion chamber. This introduces a plurality of additional design considerations for both the ignitor and the injector.
Thus, a need exists for an efficient, cost effective ignitor which may communicate directly with the combustion chamber rather than requiring the complexity of additional valves or flow control devices to deliver ignitor fluid through the injector.
Another need exists for a modular design for an ignitor allowing faster assembly and interchangeability of parts.
A further need exists for a method of joining two structural members while providing for disassembly at a later date.
Consequently, it is a primary object of the present invention to provide a cost effective ignitor for use with rocket engines, including the MC-1 engine.
It is another object of the present invention to provide an ignitor with purge grooves providing side chamber injection of hypergolic fluid to reduce the complexity of the combustion chamber injector.
Accordingly, the present invention provides an ignitor having a cartridge contained within end caps. Each of the end caps contains rupture disc assemblies. A piston is located within the cartridge and is moveable from one end of the cartridge to the other, a discharge end. The ignitor is designed to provide a low pressure, hypergolic liquid to produce a sustainable ignition source for a rocket engine chamber.
The cartridge is filled with a mixture of hypergolic fluid, Triethylaluminum and Triethylborane (TEA/TEB). A first rupture disc is ruptured to provide the motive force to drive the piston. As the piston moves toward the discharge end, the second rupture disc ruptures to deliver the hypergolic fluid into the combustion chamber. At the discharge end of the cartridge are two purge grooves which allow for fuel purging at a reduced flow rate after the TEA/TEB has been expelled to remove residual hypergolic fluid from the cartridge.